refactoring: simplified the validity check of the config before connection

- improved project structure

client/ui/models/servers_model.cpp

@@ -261,7 +261,7 @@ void ServersModel::setProcessedServerIndex(const int index)
     updateContainersModel();
     if (data(index, IsServerFromGatewayApiRole).toBool()) {
         if (data(index, IsCountrySelectionAvailableRole).toBool()) {
-            emit updateApiLanguageModel();
+            emit updateApiCountryModel();
         }
         emit updateApiServicesModel();
     }

client/ui/models/servers_model.h

@@ -140,7 +140,7 @@ signals:
     void defaultServerContainersUpdated(const QJsonArray &containers);
     void defaultServerDefaultContainerChanged(const int containerIndex);
 
-    void updateApiLanguageModel();
+    void updateApiCountryModel();
     void updateApiServicesModel();
 
 private: